The present invention relates generally to a cardiac valve suitable for implantation into mammalian subjects in need thereof. More particularly, the present invention pertains to a prosthetic transluminal plunger and cage cardiac valve that employs such plunger free to reciprocally move within a transluminal cage member under the influence of pressure differentials due to systole and diastole. It is desirable, although not essential to the present invention, that the prosthetic cardiac valve be capable of being delivered using endovascular techniques and being implanted at an intracardiac, intra-arterial, or intravenous site without the need for anatomic valve removal. Placement of the valve can be at an anatomical site of a damaged valve or in the descending thoracic aorta, depending on the tolerance of the patient. The former can be accessed through a trans-arterial or transcardiac approach; the latter through upper or lower extremity arterial access.
The prior art discloses percutaneously delivered prosthetic ball and cage valves. One such valve is made of shape memory nitinol and consists of a stent and a flow regulation mechanism. The stent comprises a meshwork or braiding of nitinol wire with trumpet like distal and proximal flares. The purpose of the stent is to maintain a semi-ridged patent channel through a diseased cardiac valve after initial balloon dilation. The flared ends are intended to maintain the position of the stent component across the valve thereby anchoring the vascular device. The flow-regulation mechanism includes a caged ball delivered secondary to the stent, thus requiring two catheters for delivery in addition to any initial valvuloplasty, which increases the time, costs, risks, difficulty and trauma associated with a percutaneous procedure. Due to the flared ends, this valve may be problematic for implantation in a patient's descending aorta. Further, the tines of the ball cage may prevent a solid continuous contact with the braided stent therefore allowing for leakage. Also, the portion of the ball cage where the tines come together with the anchor funnel would be obstructive to the flow, leading to thrombosis.
Another such valve comprises a cage mechanism comprised of a multiplicity of crisscrossed wires connected to a self-expanding stent and a seal ring connected thereto via a single stainless steel rod. A first catheter is used for implantation of the seal ring, cage, and stent, which is disposed between the ring and a cage mechanism. A second catheter is required for implantation of the balloon, which seals against the ring and allows fluid flow through the cage. Because opposite ends of the valve are connected only by the single rod, the valve may be problematic with regard to longitudinal stability.
A need exists for an improved transluminal valve of size and configuration such that the improved valve is implantable via a single catheter sheath. The improved valve would benefit from having a sturdy and durable construction with uniform geometry inherently afforded by a plunger and cage valve comprising a monolithic cage and a plunger both potentially made from multiple vacuum deposited material layers. Coverage of a portion of the monolithic cage with endothelial cells may be enhanced by depositing controlled heterogeneities along the portion of the cage. Further, patients needing transluminal valves are typically older, debilitated, and unlikely to tolerate major surgery and a significant portion of the morbidity and mortality associated with current transluminal valve placement is related to the large diameter and low flexibility of the introducer systems. Thus, the improved cardiac valve would further benefit from being sized to fit a 12-14 F introducer, thereby reducing the potential for stroke, hemorrhage, lower extremity ischemia, and other serious complications. The present invention solves these problems, as well as others.